You may have noticed that some exchanges have temporarily suspended withdrawals and wondering what’s going on or more importantly, what’s being done about it. You can be rest assured that we have identified the issue and are collectively and collaboratively working on a solution.

Somebody (or several somebodies) is taking advantage of the transaction malleability issue and relaying mutated versions of transactions. This is exposing bugs in both the reference implementation and some exchange’s software.

We (core dev team, developers at the exchanges, and even big mining pools) are creating workarounds and fixes right now. This is a denial-of-service attack; whoever is doing this is not stealing coins, but is succeeding in preventing some transactions from confirming. It’s important to note that DoS attacks do not affect people’s bitcoin wallets or funds.

Users of the reference implementation who are bitten by this bug may see their bitcoins “tied up” in unconfirmed transactions; we need to update the software to fix that bug, so when they upgrade those coins are returned to the wallet and are available to spend again. Only users who make multiple transactions in a short period of time will be affected.

As a result, exchanges are temporarily suspending withdrawals to protect customer funds and prevent funds from being misdirected.

Transaction malleability has been known about since 2011. In simplest of terms, it is a small window where transaction ID’s can be “renamed” before being confirmed in the blockchain. This is something that cannot be corrected overnight. Therefore, any company dealing with Bitcoin transactions and have coded their own wallet software should responsibly prepare for this possibility and include in their software a way to validate transaction ID’s. Otherwise, it can result in Bitcoin loss and headache for everyone involved.

Bitcoin is no longer in Phase 1 of its evolutionary cycle. I believe Phase 2 for Bitcoin began in earnest back in November 2013, when the Senate Committee on Homeland Security and Governmental Affairs held its first hearings on the topic. Those hearings made it clear that, at least for the moment, no significant roadblocks would be put in place to prevent people from transacting with one another using the crypto-currency. Phase 2 also saw the largest Bitcoin investment to-date, a $25 million infusion led by Silicon Valley VC firm Andreessen Horowitz, as well as acceptance by major U.S. retailers, with Overstock being the most significant. Bitcoin is becoming serious, and serious means serious accountability.

As a free market currency, the market will decide the products required to keep the Bitcoin protocol open and functioning to its highest potential.